Hydraulic assembly for a hydraulic vehicle brake system with traction control

ABSTRACT

The invention relates to a hydraulic assembly of a vehicle brake system with traction control. Hydraulic assemblies include a housing block, which is to be fitted with hydraulic components, and an electronic control unit for activating the components. It is known for a hydraulic connection for a pressure sensor to be provided on a housing block and for the signal of the pressure sensor to be taken into consideration for brake pressure regulation in the control unit. The invention proposes an advantageous arrangement of at least one second hydraulic connection for a second pressure sensor on the housing block in combination with blind bores of the hydraulic connections. The blind bores can be positioned in a variable fashion and formed with different lengths during the production of the housing block. In this way, it is possible for the pressure in different hydraulic partial regions of a vehicle brake system to be sensed in an application-specific manner. The number of such hydraulic connections for pressure sensors has no influence on the external dimensions of the housing block.

PRIOR ART

The invention is based on a hydraulic assembly for a vehicle brakesystem with traction control in accordance with the characteristics ofthe preamble to claim 1.

Hydraulic assemblies for vehicle brake systems with traction controlcomprise a housing block and an electronic control unit. The housingblock has many recesses for hydraulic components, such as solenoidvalves, pumps or reservoirs. Connections for the wheel brakes of avehicle brake system and for a master cylinder of a vehicle brake systemare also embodied on the housing block. Bores in the interior of thehousing block make hydraulic connections among these receptacles. Thecomponents are typically interconnected in two separate brake circuits.A housing block embodied in this way is known for instance from GermanPatent Disclosure DE 102 37 163 A1.

The aforementioned electronic control unit evaluates signals fromsensors at the wheels of the vehicle, which each detect the prevailingslip conditions, and from sensors at the brake pedal of the mastercylinder that detect its actuation and the scope of that actuation. Inthe control unit, the arriving signals are further processed intotrigger signals. With these trigger signals, among other things thesolenoid valves and the housing block are triggered, in order toregulate the brake pressure appropriately as a function of theparticular slip conditions at the wheels of the vehicle.

It is moreover known to provide the housing block with a single pressuresensor. Typically, this pressure sensor detects the pressure at one ofthe connections with a master cylinder and thus furnishes the controlunit with a further signal for controlling a vehicle brake system. Inthe brochure Fahrstabilisierungssysteme [Travel Stability Systems] inthe Gelbe Reihe [Yellow Series] by Robert Bosch GmbH, 2004 Edition, page90, FIG. 1, a hydraulic assembly sold on a large scale shown in anexploded view. This hydraulic assembly has a pressure sensor 9 that isdisposed away from an imaginary center axis through the housing block.

It is disadvantageous that with a single pressure sensor, exactconclusions about the pressure conditions of all the hydraulic portionsof the vehicle brake system cannot be drawn. Computed or estimatedmodels based on the single measured value involve a risk of error, whichnecessarily worsens the quality of control in such vehicle brakesystems.

Advantages of the Invention

By comparison, a hydraulic assembly for a hydraulic vehicle brake systemwith traction control as defined by claim 1 has a housing block which isprovided with at least one second connection for a second pressuresensor. Hydraulic contacting of the pressure sensors is made by means ofblind bores extending in the interior of the housing block. These borescan be produced relatively simply at little expense. The externaldimensions of the housing block are changed if at all onlyinsignificantly by the additional connection. By the at least one secondpressure sensor, a second portion of a vehicle brake system that issubjected to pressure can be sensed, and thus the quality of regulationin the vehicle brake system can be improved. The blind bores can vary intheir disposition and lengths, and as a result, different hydraulicportions of the vehicle brake system can be sensed. This choice can bemade specifically for a particular application and need not be fixed infinal form until in the course of the metal-cutting machining of thehousing block. The pressure sensors are mounted on a common exterior ofthe housing block, and that exterior is also suitable for mounting theelectronic control unit. This simplifies transmission of the signalsfrom the pressure sensors to the electronic controller.

It is even feasible to dispose a further, second connection for anadditional second pressure sensor in such a way, without having toincrease the external dimensions of the housing block. For themanufacturers of motor vehicles, compact dimensions of the housing blockmake a powerful argument, since the available installation spaces invehicles are intrinsically limited.

Further advantages or advantageous refinements of the invention willbecome apparent from the dependent claims or from the ensuingdescription.

DRAWING

One exemplary embodiment of the invention is shown in the drawing andexplained in detail in the ensuing description. The sole FIGURE of thedrawing, in a perspective view, shows a housing block of a hydraulicassembly along with its bores and recesses, in a preferred installedposition.

DESCRIPTION OF THE EXEMPLARY EMBODIMENT

The housing block 10 of a hydraulic assembly, shown in the drawing,comprises a metal block, in which many recesses have been made bymetal-cutting machining. Each of these recesses discharges at one of theexteriors of the housing block 10 and ends in the form of a blind borein the interior of the housing block 10. The various recesses arehydraulically interconnected to form brake circuits, by means of boresextending horizontally and vertically in the interior of the housingblock 10.

The drawing shows a view at the front side of a housing block 10. Thisfront side may be intended for later securing the electronic controlunit to it. A total of twelve identical circular valve bores 12discharge to the outside at the front side. These valve bores 12 aredistributed in four parallel, horizontal rows 14, 16, 18, 20, which aredisposed at different levels. In an ensuing assembly process, solenoidvalves are inserted into the valve bores 12.

On the front side of the block, hydraulic connections 22, 24, 26 canalso be seen. These connections 22-26 are located in the lower third ofthe housing block 10. A first connection 22 is disposed between the twovalve bores 12 of the fourth row 20 on a center axis 28 extendingvertically through the housing block 10. The connections 24 and 26 areraised compared to the first connection 22, being disposed in the regionbetween the third row 18 and the fourth row 20 of valve bores 12. Theseso-called second connections 24, 26 are placed laterally offset withrespect to the center axis 28. They are approximately in alignment belowthe two inner valve bores 12. All three connections 22-26 form thecorner points of an imaginary triangle, so that there is both ahorizontal and a vertical spacing between the first connection 22 andeach of the second connections 24, 26. The connections 22-26 areequipped with pressure sensors (not shown) at a later time.

On the back side of the housing block 10, located opposite the frontside and toward the back in the drawing, a drive chamber 30 can be seen,which is intended for receiving a pump drive. This drive chamber 30 islocated in the drawing above the two second connections 24 and 26 forpressure sensors, approximately at the level of the third row 18 ofvalve bores 12. Pump bores 32, 34 extend to both sides of this drivechamber 30. These pump bores are aligned with one another and extendhorizontally through the housing block 10. The pump bores 32, 34discharge to the outside toward the left and right exterior,respectively, of the housing block 10 and are intended for receivingpump elements, not shown, that are driven by the pump drive, also notshown, to execute a reciprocating stroke motion.

Two master cylinder connections 36, 38 extend to the outside toward theback side of the housing block 10. These connections are locateddirectly below the top of the housing block 10. By these master cylinderconnections 36, 38, a hydraulic line connection of the hydraulicassembly with a master cylinder is established, for actuation of avehicle brake system by the driver.

Four wheel brake cylinder connections 40, 42, 44, 46 are provided,located side by side, on the top side of the housing block 10. Theyserve to connect brake lines that connect to wheel brakes of a vehiclebrake system to the hydraulic assembly. The two inner wheel brakecylinder connections 42 and 44 are in contact for instance with thewheel brakes at the right rear (RR) and left rear (LR) of the vehicle.

On the underside of the housing block 10, opposite the top side,finally, two reservoir chambers 48 can also be seen, which are eachassociated with one of the brake circuits of a vehicle brake system.

With regard to the bores in the housing block 10 for hydraulicallylinking the aforementioned recesses with one another, these will bedescribed below only to the extent necessary for understanding theinvention. For technical production reasons, these bores extendhorizontally or vertically in the housing block 10. Bores not explicitlydescribed, whose functionally dictated placement and embodiment on thehousing block 10 are general prior art and will accordingly not bedescribed.

One essential feature for the invention, among others, is the hydrauliccontacting, described below, of the connection 22-26 for the pressuresensors. This is effected by means of a respective blind bore 50, 52, 54associated with one of the connections 22, 24, 26. All the blind bores50-54 extend in a common sectional plane through the housing block 10.The associated connections 22-26 for the pressure sensors are eachlocated in the surrounding of the inner, closed end of a respective oneof the blind bores 50-54.

The first connection 22, disposed on the vertical center axis 28 throughthe housing block 10, is contacted by means of a first, horizontallyoriented blind bore 50 that discharges to the exterior, on the left inthe drawing, of the housing block 10. This first blind bore 50penetrates a valve receptacle bore 12 in the lowermost, fourth row 20.This valve bore 12 is intended for receiving a so-called switchovervalve. Inside a vehicle brake system, switchover valves have thefunction of controlling an existing hydraulic communication of one ofthe master cylinder connections 36, 38 with the wheel brake connections40-46 of an associated brake circuit of the vehicle brake system. Thefirst pressure sensor, to be disposed at the first connection 22, isaccordingly capable of sensing the pressure level prevailing at themaster cylinder connection 36.

In the course of further assembly of the hydraulic assembly, the firstblind bore 50 is closed off from the surroundings. To that end, a ballis typically used, which is press-fitted into the housing block 10 inthe discharge region of the blind bore 50.

The two second connections 24 and 26 for pressure sensors arehydraulically supplied via a respective second blind bore 52, 54. Thesesecond blind bores 52, 54 extend parallel to one another in the verticaldirection. They are disposed with spacing on both sides from the centeraxis 28 of the housing block 10 and thus form a right angle W with thefirst blind bore 50 that leads to the first connection 22. The secondblind bores 52, 54 discharge the two inner wheel brake connections 42,44 at the top side of the housing block 10 and cross two respectivevalve bores 12, disposed one below the other, of the first row 14 andsecond row 16. Solenoid valves by way of which a pressure buildup in thewheel brakes can be controlled are located in the first row 14 of valvebores 12 that are oriented toward the top side of the housing block 10,while solenoid valves by way of which a pressure buildup in thecorresponding wheel brake is effected are located in the second row 16below the first. The pressure sensors associated with the secondconnections 24, 26 thus detect the pressure conditions at wheel brakesthat preferably belong to different brake circuits of the vehicle brakesystem.

As explained, in the described variant embodiment of the invention, thefirst connection 22 for a pressure sensor communicates with theconnection 36 of the master cylinder, while the two second connections24, 26 are connected to the wheel brakes of different brake circuits.This contacting is merely an example. While maintaining the position ofthe described connections 22-26 for the pressure sensors, it is possibleby a change in the direction in which they extend, in the horizontal orvertical positioning of the blind bores 50-54, and/or by varying thelength to which these blind bores 50-54 extend, to establish pressurefluid communications with other hydraulic portions of a vehicle brakesystem. For instance, it would be conceivable for the respective secondconnection of the master cylinder 36 or 38 to be connected, instead ofto a wheel brake connection 40-46, to at least one of two secondconnections 24, 26. It is understood that not all three connections 22,24, 26 for pressure sensors have to be provided. Often, sufficientimprovement in the quality of regulation of a vehicle brake system forthis particular use can be attained with only a single second connection24 or 26 for a pressure sensor.

Further modifications or additions to the exemplary embodiment describedare possible without departing from the fundamental concept of theinvention.

1-10. (canceled)
 11. A hydraulic assembly for a hydraulic vehicle brakesystem with traction control, comprising: a housing block havingreceptacles, provided on the housing block, the receptacles provided forreceiving hydraulic components for regulating the brake pressure at thewheel brakes of a vehicle brake system, such as pumps, solenoid valvesand reservoirs; the housing block having bores, that carry pressurefluid and switch the receptacles to at least one brake circuit; thehousing block having hydraulic connections for the wheel brakes of thevehicle brake system, for a master cylinder of the vehicle brake system,and having a first hydraulic connection for a first pressure sensor thatdetects the hydraulic pressure in a hydraulic portion of the vehiclebrake system; and at least one second hydraulic connection for a secondpressure sensor being embodied on the housing block, wherein the firstand the second hydraulic connection of a pressure sensor are eachdisposed on closed ends, located inward, of blind bores that carrypressure fluid, wherein the blind bores put the first and secondconnection for a pressure sensor into contact with different receptaclesfor solenoid valves for regulating the brake pressure.
 12. The hydraulicassembly as defined by claim 11, wherein the first connection for apressure sensor is placed on a center axis extending vertically throughthe housing block, the at least one second connection for a pressuresensor is disposed on the housing block with horizontal spacing and withvertical spacing compared to the first connection for a pressure sensor.13. The hydraulic assembly as defined by claim 12, wherein the firstconnection for a pressure sensor is disposed remote from the wheel brakeconnections of the vehicle brake system, relative to the at least onesecond connection for a pressure sensor.
 14. The hydraulic assembly asdefined by claim 12, wherein the blind bores, for hydraulicallycontacting the connections of the pressure sensors, extend in a commonsectional plane through the housing block and are oriented horizontallyand/or vertically.
 15. The hydraulic assembly as defined by claim 13,wherein the blind bores, for hydraulically contacting the connections ofthe pressure sensors, extend in a common sectional plane through thehousing block and are oriented horizontally and/or vertically.
 16. Thehydraulic assembly as defined by claim 12, wherein the blind bores forcontacting the connections of the pressure sensors form an essentiallyright angle with one another.
 17. The hydraulic assembly as defined byclaim 13, wherein the blind bores for contacting the connections of thepressure sensors form an essentially right angle with one another. 18.The hydraulic assembly as defined by claim 14, wherein the blind boresfor contacting the connections of the pressure sensors form anessentially right angle with one another.
 19. The hydraulic assembly asdefined by claim 12, wherein the blind bore to at least one secondconnection for a pressure sensor hydraulically connects a wheel brakeconnection with the valve bores of two solenoid valves, and a solenoidvalve that controls the pressure buildup in a wheel brake is insertedinto one of the valve bores, and a solenoid valve that controls thepressure buildup of that wheel brake is inserted into the respectiveother valve bore.
 20. The hydraulic assembly as defined by claim 13,wherein the blind bore to at least one second connection for a pressuresensor hydraulically connects a wheel brake connection with the valvebores of two solenoid valves, and a solenoid valve that controls thepressure buildup in a wheel brake is inserted into one of the valvebores, and a solenoid valve that controls the pressure buildup of thatwheel brake is inserted into the respective other valve bore.
 21. Thehydraulic assembly as defined by claim 14, wherein the blind bore to atleast one second connection for a pressure sensor hydraulically connectsa wheel brake connection with the valve bores of two solenoid valves,and a solenoid valve that controls the pressure buildup in a wheel brakeis inserted into one of the valve bores, and a solenoid valve thatcontrols the pressure buildup of that wheel brake is inserted into therespective other valve bore.
 22. The hydraulic assembly as defined byclaim 16, wherein the blind bore to at least one second connection for apressure sensor hydraulically connects a wheel brake connection with thevalve bores of two solenoid valves, and a solenoid valve that controlsthe pressure buildup in a wheel brake is inserted into one of the valvebores, and a solenoid valve that controls the pressure buildup of thatwheel brake is inserted into the respective other valve bore.
 23. Thehydraulic assembly as defined by claim 11, wherein the connections ofthe pressure sensors discharge toward a common exterior of the housingblock.
 24. The hydraulic assembly as defined by claim 15, wherein theconnections of the pressure sensors discharge toward a common exteriorof the housing block.
 25. The hydraulic assembly as defined by claim 11,wherein the valve bores of the solenoid valves discharge at the commonexterior of the housing block.
 26. The hydraulic assembly as defined byclaim 24, wherein the valve bores of the solenoid valves discharge atthe common exterior of the housing block.
 27. The hydraulic assembly asdefined by claim 11, wherein the first connection for a pressure sensorcommunicates hydraulically with one of the master cylinder connectionson the housing block, and the at least one second connection for apressure sensor is put into contact with a wheel brake connection of thehousing block.
 28. The hydraulic assembly as defined by claim 26,wherein the first connection for a pressure sensor communicateshydraulically with one of the master cylinder connections on the housingblock, and the at least one second connection for a pressure sensor isput into contact with a wheel brake connection of the housing block. 29.The hydraulic assembly as defined by claim 11, wherein the firstconnection for a pressure sensor and the at least one second connectionfor a pressure sensor are put into contact with master cylinderconnections that are separate from one another.
 30. The hydraulicassembly as defined by claim 28, wherein the first connection for apressure sensor and the at least one second connection for a pressuresensor are put into contact with master cylinder connections that areseparate from one another.